Even minimal postoperative residual NMB with a train of four ratio (TOF) of 0.8 is associated with impaired respiratory function as witnessed in reductions of forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) in healthy volunteers. Moreover, a TOF < 0.7 correlates with increased postoperative respiratory complications due to the inability to swallow normally leading to aspiration, atelectasis and pneumonia. However, neuromuscular blocking agents not only impair respiratory function due to skeletal muscle relaxation. Also the body's response to hypoxia is impeded due to carotid body chemoreceptor suppression. Worryingly, reversal of NMB with neostigmine can lead to respiratory complications such as bronchospasm and even induce neuromuscular transmission failure in patients who already recovered from NMB.